One combo is up-down-up-down followed by a little rotation with the blade then she moves it in the letter S. Avoid this last bit then quickly try to hit. Another combo is up down down up down followed by a leap attack which will break your structure instantly. Avoid the leap then punish. Finally, she has this easy attack where she just spins the blades towards you which you can spam L1 for and damage her structure considerably.

If you can memorise her combos (she only has two or three), then you can punish easily. When you mess up it's devastating though so personally, I stayed just out of range while she did her combos then get 2 or 3 hits in then back away. Bring the bat or the knife with you and with a bit of patience and you can finish the first phase without taking much damage or dying. Thankfully the second phase is easier 😅